Vector group test for transformer

Vector Group Test of Power Transformer. The vector group of transformer is an essential property for successful parallel operation of transformers. Hence every electrical power transformer must undergo through vector group test of transformer at factory site for ensuring the customer . Test Conditions for various vector groups commonly under use are listed along with pictorial representation.

Assuming the reader has sufficient exposure to transformer winding connections.

Transformer is the most important unit in an electrical distribution network.

Three phase transformer consists of three sets of primary windings, one for each phase, and three sets of secondary windings wound on the same iron core.

All transformers are subjected to various tests at the manufacturer‟s test laboratory before despatch to the destination of erection. Measurement of turn‟s ratio is one of the routine tests which each transformer has to undergo. It is crucial to know the vector group of the transformer when trying to parallel the transformer.

Also measurement of short circuit impedance and load loss at working temperature and its actual before and after short circuit test. All the transformers with same vector ground have same phase sequence and phase divergence between primary and secondary. So before procuring one electrical power transformer , one should ensure the vector group of the transformer , whether it will be matched with his or her existing system or not.

In electrical engineering, a vector group is the International Electrotechnical Commission (IEC) method of categorizing the high voltage (HV) windings and low voltage (LV) winding configurations of three-phase transformers. The internet does not specify test procedure accurately unfortunately. No-load losses and current Test. Short-circuit impedance and load loss Test. Determining the connection ( vector ) group is valid only in three phase transformers.

The high voltage winding is shown first (as reference) and the other windings follow it. If the vector directions of the connection are correct, the bridge can be balanced. Also, checking the connection group or polarity is . The phase sequence of the supply should.

Hence every power transformer must undergo through vector group test of transformer at factory site for ensuring the customer specified vector group of transformer. Introduction to the Delta Wye . In the factory, the transformer ratio of each tap and the vector group are verified during production and acceptance testing. On site, ratio and magnetization current measurements are performed in order to assess possible winding damage, such as short circuits between windings or between turns. Procedure for conduting vector group test on power transformers.

In order to find the source and reason for high gas values, further tests have to be performed on the transformer.